Lapping machine



1959 P. c. SCIBETTA ETAL 2,393,710

1NVENTOR5. PAUL G. SCIBETT'A LOUIS B.H|GDON Un ted S tes Patent 2,898,710 LAPPING MACHINE Paul c. Scibetta, Niagara Falls, N.Y., and Louis B. Higdon, Rockville, Md., assignors to the United States of America as represented by the Secretary of the Navy Application May 27, 1958, Serial No. 738,246

2 Claims. (Cl. 51-157) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This application relates to a machine for producing final lapped finish on a crowned roll.

It is an object of this invention to provide a simple lapping machine for producing a fine finish on a generally cylindrical surface having a crown therein.

It is another object of this invention to provide a lapping machine having an instantaneously adjustable stationary lap held in continuous engagement with a reciprocating and rotating crowned work piece.

Still another object is the provision of a randomly indexing lapping machine which is inexpensive to manufacture and which is exceptionally efficient in lapping crowned rolls.

These and many other objects will become more readily apparent when the following specification is read and considered in conjunction with the attendant drawing showing in perspective apparatus embodying the principles embodied in this invention.

Referring now with greater particularity to the single figure of the drawing, the machine comprises a bed 11 having a dovetailed groove 12 formed in its upper surface and extending across the length of the bed. A block 13 is disposed in groove 12 and is fixed therein by a plurality of screws or bolts 14 and forms one side of dovetail groove 12. If for any reason it becomes necessary to alter the width of groove 12 the block 13 may be adjusted by removing bolts 14, and sliding the block to a different position. Disposed within the dovetailed way 12 is a carriage 1-6 composed of a base 17 and a pair of upright end plates 18 and 19 respectively. A shaft 21 rotatably supported at either end by end plates 18 and 19 has a spiral groove 24 extending along the major portion of its length. A hardened steel pointer or finger 26 is rigidly connected to the bed 11 by bracket 22 and rides in spiral groove 24 for the purposes to be described more fully hereinafter.

A motor 28 is connected to the input of a speed reduction box 29 which has its output connected to a crank arm 31. A connecting rod 32 pivotally secured to an appropriate bracket 33 in end plate 19 is connected to the crank arm to transmit reciprocatory motion to the carriage 16 as the crank arm 31 rotates.

As the carriage 16 reciprocates back and forth in the way 12, shaft 21 rotates about its axis because of the influence of the stationary pointer 26 in groove 24. A pulley 34 is fixed to shaft 21 and is operatively connected to a smaller pulley 36 which is connected to the work piece 37 rotatably disposed between the centering members 38 and 39 which are secured in end plates 18 and 19 respectively above the shaft 21. Centering member 38 extends through a suitable hole in the end plate 18 and is permanently atfixed to the adjustable center rest 41 which is secured to plate 18 by any suitable means such as screws 42. In the event that a slightly larger work piece 2 is to be lapped, the. series of spacers may be inserted between the adjustable center rest 41 and the plate 18 to accommodate a longer work piece.

The copper lap 43 is composed of an upper segment 44 and a lower segment 46 disposed between the arms of the U-shaped bracket 47 positioned above the-bed 11 by a suitable extension member 48.fixed to bed 11. Interposed between each arm of the U-shaped bracket and the corresponding segment of lap 43 is a compression spring 49 to urge the segments of the lap toward each other, this tendency being resisted by the work piece as it moves through the lap.

Formed on the second pulley 36 is a collar 51 of internal diameter sufficiently small to permit the work piece to slide through as it is mounted preparatory to lapping while a set screw 52 fixed in collar 51 exerts suflicient drag on the collar to impart rotation to the work piece as pulley 36 is rotated. However, the set screw is not tightened so much that it does not aperiodically and randomly slide on the work piece to permit indexing of the work piece with respect to shaft 21 thereby eliminating any possibility of tracking or grooving as the roll is lapped. It is to be understood, of course, that this set screw must not be positioned on the working surface of the roll in order not to mar the finish of the working surfaces of the roll.

Since the lap 43 is segmented and is spring biased, it is able to follow the variations in the crowned roll without tending to grind down the crowned portion of the roll as it reciprocates and oscillates through the lap. It has been found in order to get best results with this machine it is necessary that the lap be formed in approximately equal half segments, for example tri-segmented lap is not suitable because the lap does not tend to open and close uniformly when the crowned piece is moved through it. Although a two segmented lap necessitates the use of different sized laps for various diameter rolls, it is amply compensated for by the performance of the lap in finishing rolls having a crowned surface.

Although this invention has been described with reference to but one particular embodiment, it is by no means so limited and is capable of various modifications and alterations without departing from the spirit and scope thereof. Accordingly, the scope of this invention is to be determined only by the appended claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A machine for lapping the outside diameter of a crowned, generally cylindrical work piece which comprises: a bed having a guideway therein, a carriage rotatably supporting the work piece and disposed in the guideway, means connected to the carriage {or reciprocating it along the guideway, a shaft having a spiral groove along a portion of its length and rotatably supported by said carriage, a finger fixed to said bed and cooperating with the groove in said shaft for rotating said shaft as the carriage reciprocates in the guideway, means rotatably connecting the work piece to said shaft and aperiodically indexing the work piece with respect to said shaft, a lap support fixed to said bed, a lap disposed about the work piece and having two complementary segments each resiliently carried by the lap support to provide an internal working surface of about 360 continuously in contact with the work piece as it reciprocates and rotates through the lap.

2. A machine for lapping the outside diameter of a crowned, generally cylindrical work piece which comprises: a bed having a guideway therein, a carriage rotatably supporting the work piece and disposed in the guideway, means connected to the carriage for reciprocating it within the guideway, a shaft having a spiral groove along its length and rotatably supported by said carriage, means fixed to said bed and cooperating with the groove in said shaft for rotating said shaft as it reciprocates, a firstpulley fixed to said shaft, a second pulley disposed about ,the work piece adjacent to one end, belt means 'rotatably connecting said first and second pulleys, a set screw in theisecond pulley and loosely engaging the Work piece torandomly index thework piece with respect to said shaft, a'lap support fixed to said bed and having a 'U-shaped portion overhanging the guideway, a pair of springs each fixed to a respective arm of the U-shaped portion, a pair 'of complementary lap segments providing an internal working surface of about 360, each of said lap segments being fixed respectively to one of sa-id springs, thereby to provide a lap of continuously adjust- -able internal diameter to accommodate the crown on the Work piece as it reciprocates through the lap.

Artman Aug. 24', 1886 Ellis Sept. V2, 1947 

